Geology of McBride map-area, British Columbia

McBride map-area, about 5,800 square miles in east-central British Columbia, includes parts of the Interior Plateau, Cariboo Mountains, Rocky Mountain Trench, Rocky Mountains, and Foothills. About 25,000 feet of Proterozoic (Windermere) and Lower Cambrian strata can be correlated in some detail from Rocky to Cariboo Mountains. The precision of the correlation, based partly on lithologic similarities, depends primarily on the obvious equivalence of the fossiliferous Lower Cambrian carbonate (Mural Formation) in each sequence. The stratigraphy above the Lower Cambrian differs sharply from one side of the Trench to the other. In Rocky Mountains carbonate-shale Cambro-Ordovician sequence, much like that at Mount Robson, becomes shaly near the Trench where overlying Silurian strata include volcanic rocks. The Upper Devonian to Permian and Mesozoic sedimentary rocks of the Front Range and Foothills are similar to those of the well-known Jasper-Banff region. West of the Trench Lower Cambrian beds pass upward to a Middle (?) and Upper Cambrian shale sequence that is unconformably overlain by Lower Devon ion and (?) younger sedimentary rocks which in turn lie discordantly below conglomerate and basaltic pillow lava at least partly of Lower Mississippian age. These are followed by unconformably overlying Upper Triassic (?) phyllite and shale. The Upper Triassic and Lower Jurassic volcanic rocks of the Interior Plateau are just west of the map-area. Minor dykes and sills and a small body of serpentinite are the only known intrusive rocks in the map-area. Typical Rocky Mountain thrust faults are confined to the eastern Main Ranges, Front Ranges, and Foothills. Farther west in Rocky Mountains and also west of the Trench folding is prominent and recognizable faults are steeply dipping. In Cariboo Mountains folds in structurally deep beds apparently upward to a highly faulted and little folded terrain. To date the only significant mineral production was from the gold placer and lode deposits near Barkerville. The Bowron River coal deposits have been extensively explored. SmalI copper showings are known near Dome Creek.